1. Field of the Invention
The invention relates to a device for connecting two electrical conductors, composed of a metal clamp constructed from a pipe piece, wherein the clamp has in its wall at least two throughholes provided with a thread for receiving clamping screws provided with an external thread.
2. Description of Related Art
Devices of this type are known and available on the market. They are used, for example, for connecting the conductors of energy cables which are composed preferably of copper or aluminum. For securing and contacting the conductors in the damp, clamping screws are used which are constructed, for example, as shearing screws. The heads of such screws shear off when a certain moment is reached, i.e., when reaching a sufficiently high contact force between screw and conductor.
The contact force produced by the clamping screws effects the connection of the conductor with the clamp and the connection of the individual wires of the conductor. The connection is to be maintained during the entire demanded service life of the device. The electrical current flows in such a device from a conductor through the clamp to the other conductor having relatively high transmission resistances.
In multiple-wire conductors, there is the additional fact that the individual wires of the conductors rub against each other when compacting occurs as a result of tightening the clamping screw. This produces the result that in the interior of the conductor a pressure is produced which is smaller than the pressure at the surface. This may lead to problems when connecting multiple-wire conductors with large cross-sections or in segmented conductors, so called “Milliken” conductors. When the contact of the individual wires in the interior of the conductor is insufficient, heating occurs which is above average. In conductors of aluminum, this heating additionally leads to increased flux of the material and, as a result, after a short time already to a further reduction of the contact pressure. The electrical connection between the conductors becomes then useless relatively quickly.
It is the object of the invention to construct the above-described device in such a way that the electrically conducting connection between the two conductors to be connected can be improved permanently.
In accordance with the invention, the object is met in that                in the pipe piece of the clamp between the two throughholes, at least one middle throughhole provided with a thread for receiving a fixing screw provided with an external thread is mounted, which has a narrowing, approximately conical tip which, in the mounted position, rests tightly against the end faces of the two conductors inserted into the pipe piece,        the tip provided with an external thread is screwed into a recess of the fixing screw provided with an internal thread, and        the external thread of the tip is constructed with an external thread directed oppositely of the external thread of the fixing screw,        
In this device, the two conductors are connected directly and at least essentially without gaps in the clamp through the conical tip of the fixing screw which tightly rests against the end faces of the two conductors. Consequently, a substantial portion of the current flows through the advantageously conical tip from one conductor to the other. The tight contact of the tip at the end faces of the two conductors is ensured especially by the fact that the tip with a thread which is opposite the external thread of the fixing screw is screwed into the fixing screw. As a result, when tightening the fixing screw, the advance of the tip is greater than the advance of the fixing screw itself This ensures that the tip penetrates deeply into the interior of the clamp and is in the clamp pressed between the end faces of the two conductors, without the pipe piece of the clamp having to have a particularly large wall thickness.